Generally, to increase efficiency of an IC fabrication facility, semiconductor manufacturers seek to reduce the number of processes and apparatus that are utilized in the fabrication facility, or maximize their efficiency. In some instances, the size of an apparatus may be reduced to allow for a more compact facility layout or for additional apparatus in the same layout. Semiconductor fabrication facilities utilize various processes and apparatus in fabricating IC devices on semiconductor wafers, which may be stored and transported, from one processing station/apparatus to a next one. While the wafers are stored or transported, they may be subjected to direct or wafer-to-wafer airborne molecular contamination (AMC) or moisture causing failures during subsequent fabrication processes. In some instances, additional processes and an inert gas (e.g., nitrogen (N2)) may be utilized to overcome some of the contamination/moisture issues.
FIG. 1A illustrates an example wafer processing system that includes a wafer processing apparatus 101 interfacing with an equipment front-end module (EFEM) 103 (e.g., a transfer chamber), which interfaces with load ports (LP) 105. A front opening unified pod (FOUP) 107 may be used to store wafers as well as to dock at a LP 105 for delivering wafers to the processing apparatus 101. However, prior to or post processing of the wafers, they may be contaminated by AMC or moisture (e.g., directly or wafer-to-wafer) as the wafers are transferred and stored in the FOUP 107. Additionally, the material (e.g., plastic) of a FOUP 107 may absorb contaminants and later disperse them in the pod environment causing contamination of the wafers.
FIG. 1B illustrates another example wafer processing system where LPs 109 may be purged by using a suitable purging agent (e.g., N2), which may reduce AMCs and moisture in the FOUP 107 during storage and transportation of the wafers. However, this approach would require new LPs 109 with a high consumption of purging agent, purging of the FOUP in storage to maintain the FOUP environment, and frequent cleaning of the FOUPs. Additionally, although the LPs 109 and FOUPs 107 may have a purged atmosphere, the EFEM 103 does not and may still cause contamination of the wafers as they are transferred from and to the LPs 109.
FIG. 1C illustrates another example wafer processing system where wafer pods 111 interface with LPs 113, which directly interface with the processing apparatus 101. This configuration requires significant tool reconfiguration; for example, replacing load locks, modifying system software, and a faster automated material handling system (AMHS).
A need therefore exists for a methodology and system to efficiently reduce contamination of semiconductor wafers during storage and transportation of the wafers while reducing cost, cycle time and process steps and tools.